在
Keras库
中,你可以使用`tf.
keras.optimizers`模块来创建并应用各种神经网络
优化器,其
中包含多种类型的衰减策略。例如,如果你想在
Adam
优化器中添加学习率衰减,可以利用`LearningRateSchedule`接口。以下是如何在Python
中实现这一点的一个例子:
```python
i
mport
tensorflow as tf
from
tensorflow.
keras.optimizers.schedules i
mport LearningRateSchedule, Expo
nentialDecay
class CustomLRSchedule(LearningRateSchedule):
def __init__(self, initial_learning_rate, decay_steps, decay_rate=0.96):
super(CustomLRSchedule, self).__init__()
self.initial_learning_rate = initial_learning_rate
self.decay_steps = decay_steps
self.decay_rate = decay_rate
def call(self, step):
return self.initial_learning_rate * (self.decay_rate ** tf.math.floor(step / self.decay_steps))
# 使用自定义学习率衰减的
Adam
优化器
initial_learning_rate = 0.001
decay_steps = 1000
custom_decay = CustomLRSchedule(initial_learning_rate, decay_steps)
optimizer = tf.
keras.optimizers.
Adam(learning_rate=custom_decay)
# 在训练循环
中,学习率会随着训练步骤自动衰减
for step in range(total_steps):
with tf.GradientTape() as tape:
# 计算梯度
gradients = tape.gradient(loss, model.trainable_variables)
optimizer.apply_gradients(zip(gradients, model.trainable_variables))
```